Vacuum cleaners of the interchangeable attachment type to which the invention relates are provided with a powered brush vacuum nozzle that is removable from the wheeled motor fan carriage so that the vacuum nozzle may be replaced with other on-the-floor attachments such as floor polishing heads, rug shampooer heads or the like, all of which have powered brushes or other elements which are interchangeably driven by the fan motor. By this means a single power source, the fan motor, is utilized both for powered brush vacuum cleaning and for the different operations performed by the attachments that are substituted for the vacuum nozzle.
In vacuum cleaners of this general type, it is necessary to limit the torque delivered to the driven brush within the vacuum nozzle, or to the driven elements within other substituted attachments. This is necessary both for the safety of the user and to prevent damage to the motor if an obstacle becomes lodged in the nozzle or other accessory so as to block rotation of the brush or other driven element. Torque is limited by providing a slip clutch in the drive linkage between the motor and the driven brush or other element. The slip clutch may be simply a belt-and-pulley connection utilizing a smooth belt which will slip in its pulley when a given degree of torque is exceeded.
It is obviously desirable to make it as convenient as possible for the user to change back and forth between the powered brush nozzle and one of the other attachments or to change between the other attachments, without being required to manipulate a belt lifter in order to establish and release the drive connection.
It is also desirable that the user be able to use the vacuum fan to provide vacuum for vacuum wands or other vacuum tools that do not have linkage-driven brushes or other linkage-drive elements (although some may have turbo-driven elements), and to do so without requiring removal of the mounted powered brush nozzle (or other attachment) and without having to manipulate a belt lifter in order to disconnect the powered brush or other powered element.